A connectable water supplying pipe provided in a building etc. for fire extinction, and a fluid supply pipe for water and sewage are installed by connecting pipe bodies of a predetermined length by housing type pipe joints.
For the housing type pipe joints, as a structure for avoiding detachment of a pipe body 22 from a housing 23 in a housing type pipe joint 20, a structure as illustrated in FIG. 9 in which a circular locking ridge 21 is formed on an outer peripheral surface of an end portion of the pipe body 22, the locking ridge 21 being engaged with an inner peripheral opening edge 24 of the housing 23 has been proposed (Patent Document 1).
In addition, as illustrated in FIG. 10, Patent Document 1 also discloses, as a method of forming the locking ridge on the outer peripheral surface of the end portion of the pipe body, form rolling to form the locking ridge on the outer peripheral surface of the end portion of the pipe body by rotating in a circumferential direction of a workpiece pipe body 22 while pressurizing in directions of approaching each other an inner convex roller 25 having a forming ridge 26 arranged inside the workpiece pipe body 22 and an outer concave roller 27 having a forming circular groove 28 arranged outside the workpiece pipe body 22.
Alternatively, as illustrated in FIG. 11, a joint structure for a fluid supply pipe having a circular groove 29 formed on an inner peripheral surface of a pipe body has been proposed (Patent Document 2). The joint structure for a fluid supply pipe proposed in Patent Document 1 employing a locking ridge formed on the outer peripheral surface of the pipe body by a form rolling method is free from risk of increased passage resistance due to reduced inner diameter of the pipe body, compared to the joint structure proposed in Patent Document 2. Yet alternatively, as illustrated in FIG. 12, Patent Document 3 proposes a matter in which a circular locking member 30, which is a separate part from a pipe body, is bonded onto an outer peripheral surface of the pipe body by means of a welded portion 31. However, in the case of bonding a separate part onto a supply pipe by welding, spatters attached onto the supply pipe after the welding may cause liquid leakage and damage of a sealing member, and welding quality control is therefore required. Meanwhile, the joint structure for a fluid supply pipe proposed in Patent Document 1 employing the locking ridge formed on the outer peripheral surface of the pipe body by the form rolling method allows easier formation of the locking ridge and is advantageous from a cost perspective, since such structure does not require a separate part and the locking ridge can be formed by simply form rolling an end of the workpiece pipe body.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-78052
Patent Document 2: Japanese Registered Patent No. 4774325
Patent Document 3: Japanese Registered Utility Model No. 3171690